In recent years, due to various factors, chronic diseases such as cardiovascular diseases, high blood pressure, and diabetes have been increasing. The chronic disease patients need to be treated by doctors, but should manage their own health states by periodically measuring biometric information (for example, a blood pressure, blood glucose, a heart rate (or heart pulsations), and an electrocardiogram (ECG)) by themselves.
For example, the diabetes patients need to measure blood glucose by about 6 times per day, to maintain and adjust a suitable glucose value in everyday life. Further, for example, the patients that suffer from the heart diseases such as myocardial infarction, angina pectoris, and arrhythmia need to regularly measure an ECG to identify whether the heart pulsations of the heart are normal or not.
The medical device manufacturers have developed domestic medical instruments (for example, a hemadynamometer, a blood glucose monitor, an insulin pump, a heartbeat meter, and an ECG monitor) for measuring biometric information such as blood glucose or an ECG in very various ways. Further, the standardization of the medical instruments and medical services also are being actively performed together.
Due to the development of mobile communication technologies, the portable electronic devices, such as smartphones, tablet personal computers (PCs), and wearable devices, employ some or all of the functions of other dedicated devices (for example, a medical instrument), pursuing high functionality.
When a function of a medical instrument is mounted on the portable electronic device, the portable electronic device may employ various biometric sensors.
For example, the biometric sensor may correspond to a glucose sensor that uses an electrochemical principle or an optical principle. The glucose sensor may measure blood glucose based on an electrochemical reaction or an optical reaction between blood provided in the glucose sensor and an element of the glucose sensor.
When it comes to a glucose sensor that uses an electrochemical principle, a glucose sensor strip containing blood of the user may be connected to the glucose sensor through a connector. An enzyme electrode of the glucose sensor may generate a current through an electrochemical reaction between the blood and the blood glucose of the user. The glucose sensor may detect a change in a fine current or voltage that is obtained from the electrochemical reaction, and may measure blood glucose by amplifying the fine current or voltage.
Further, for example, the biometric sensor may correspond to an ECG sensor. The heart acts as a pump that circulates blood throughout the whole human body, and is repeatedly contracted and expanded regularly. The heart may generate a fine amount of electricity whenever it is repeatedly contracted and released. Due to the weak electricity, a current flows through the human body and an electric potential is generated on a surface of the human body due to the current.
The ECG sensor may detect and amplify a fine electrical change due to the pumping operation of the heart and may output the amplified electrical change in the form of a figure. For example, the ECG sensor may detect electric potentials on the surfaces of the human body through a plurality of electrodes attached to a portion of the human body, and may output the electric potentials in a curve.
Further, for example, the biometric sensor may correspond to a photoplethysmogram (PPG) sensor. The PPG sensor may irradiate light of a specific intensity to a part (for example, a finger or a wrist) of the human body through a light emitting module. The PPG sensor may measure pulse waves by detecting the intensity of the received light that is changed by contraction and expansion of a blood vein, a change in the color of the blood, or the like, through a light receiving module.
The above-mentioned biometric sensors measure biometric information by using a very weak electrical signal or optical signal in common. Accordingly, the biometric sensor can guarantee the preciseness and reliability of measurement, only if receiving a sufficient amount of computing resources for operating the biometric sensor while receiving electric power very precisely and stably.
Further, the biometric information may be vulnerable to external noise because it is calculated based on very weak electrical/optical signals. Accordingly, the preciseness and reliability of measurement of biometric information can be improved by effectively interrupting external noise.
For example, the glucose sensor should precisely and stably receive electric power from a power source to improve the preciseness of measurement. Further, in the case of the ECG sensor, electrical noise by external stimuli also should be maximally interrupted to obtain an accurate ECG result. In the case of the PPG sensor, the light emitting module and the light receiving module should receive electric power precisely and stably to measure pulse waves of high reliability, and in particular, the light receiving module should effectively interrupt optical noise from the outside.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.